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feat: Change event name to be a label (nodeshift#15)
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* BREAKING CHANGE: Changes event metrics to use labels rather than seporate metrics

* BREAKING CHANGE: Changes metrics to use labels for circuit name rather than seporate metrics

Co-authored-by: martlandh <HarryMartland@Rentalcars.com>
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@HarryEMartland
HarryEMartland and martlandh authored Mar 13, 2020
1 parent e6284dc commit 075b033
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Showing 2 changed files with 83 additions and 75 deletions.
38 changes: 16 additions & 22 deletions index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -9,9 +9,6 @@ const client = require('prom-client');
// circuit name to pass the tests.
// More details:
// https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels
function normalizePrefix (prefixName) {
return `circuit_${prefixName.replace(/[ |-]/g, '_')}_`;
}

class PrometheusMetrics {
constructor (circuits, registry) {
Expand All @@ -22,8 +19,19 @@ class PrometheusMetrics {

this._registry = registry || client.register;
this._client = client;
this.counters = [];
this.summaries = [];
this._counter = new this._client.Counter({
name: `circuit`,
help: `A count of all circuit' events`,
registers: [this._registry],
labelNames: ['name', 'event']
});

this._summary = new this._client.Summary({
name: `circuit_perf`,
help: `A summary of all circuit's events`,
registers: [this._registry],
labelNames: ['name', 'event']
});

if (!registry) {
this.interval = this._client
Expand All @@ -40,32 +48,18 @@ class PrometheusMetrics {
return;
}
circuits = Array.isArray(circuits) ? circuits : [circuits];
let prefix;

circuits.forEach(circuit => {
prefix = normalizePrefix(circuit.name);
for (const eventName of circuit.eventNames()) {
const counter = new this._client.Counter({
name: `${prefix}${eventName}`,
help: `A count of the ${circuit.name} circuit's ${eventName} event`,
registers: [this._registry]
});
circuit.on(eventName, _ => {
counter.inc();
this._counter.labels(circuit.name, eventName).inc();
});
this.counters.push(counter);

if (eventName === 'success' || eventName === 'failure') {
// not the timeout event because runtime == timeout
const summary = new this._client.Summary({
name: `${prefix}${eventName}_perf`,
help:
`A summary of the ${circuit.name} circuit's ${eventName} event`,
registers: [this._registry]
});
circuit.on(eventName, (result, runTime) => {
summary.observe(runTime);
this._summary.labels(circuit.name, eventName).observe(runTime);
});
this.summaries.push(summary);
}
}
});
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120 changes: 67 additions & 53 deletions test/prometheus-test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -30,33 +30,37 @@ test('The factory function accept no parameter', t => {
t.end();
});

test('The factory function takes an object instead of just an Array', t => {
test('The factory function takes an object instead of just an Array', async t => {
t.plan(3);
const c1 = new CircuitBreaker(passFail, { name: 'fred' });
const prometheus = new PrometheusMetrics(c1);
await c1.fire(1);
t.equal(c1.name, 'fred');
t.ok(/circuit_fred_/.test(prometheus.metrics));
t.ok(/circuit_fred_.*perf/.test(prometheus.metrics));
t.ok(/circuit.*fred/.test(prometheus.metrics));
t.ok(/circuit_perf.*fred/.test(prometheus.metrics));
prometheus.clear();
t.end();
});

test('The factory function provides access to metrics for all circuits', t => {
t.plan(6);
const c1 = new CircuitBreaker(passFail, { name: 'fred' });
const c2 = new CircuitBreaker(passFail, { name: 'bob' });
const prometheus = new PrometheusMetrics([c1, c2]);
t.equal(c1.name, 'fred');
t.equal(c2.name, 'bob');
t.ok(/circuit_fred_/.test(prometheus.metrics));
t.ok(/circuit_fred_.*perf/.test(prometheus.metrics));
t.ok(/circuit_bob_/.test(prometheus.metrics));
t.ok(/circuit_bob_.*perf/.test(prometheus.metrics));
prometheus.clear();
t.end();
});
test('The factory function provides access to metrics for all circuits',
async t => {
t.plan(6);
const c1 = new CircuitBreaker(passFail, { name: 'fred' });
const c2 = new CircuitBreaker(passFail, { name: 'bob' });
const prometheus = new PrometheusMetrics([c1, c2]);
await c1.fire(1);
await c2.fire(1);
t.equal(c1.name, 'fred');
t.equal(c2.name, 'bob');
t.ok(/circuit.*fred/.test(prometheus.metrics));
t.ok(/circuit_perf.*fred/.test(prometheus.metrics));
t.ok(/circuit.*bob/.test(prometheus.metrics));
t.ok(/circuit_perf.*bob/.test(prometheus.metrics));
prometheus.clear();
t.end();
});

test('The factory function uses a custom prom-client registry', t => {
test('The factory function uses a custom prom-client registry', async t => {
t.plan(10);
const registry = new Registry();
const c1 = new CircuitBreaker(passFail, {
Expand All @@ -66,66 +70,73 @@ test('The factory function uses a custom prom-client registry', t => {
name: 'bob'
});
const prometheus = new PrometheusMetrics([c1, c2], registry);
await c1.fire(1);
await c2.fire(1);
t.equal(c1.name, 'fred');
t.equal(c2.name, 'bob');
t.ok(/circuit_fred_/.test(registry.metrics()));
t.ok(/circuit_fred_.*perf/.test(registry.metrics()));
t.ok(/circuit_bob_/.test(registry.metrics()));
t.ok(/circuit_bob_.*perf/.test(registry.metrics()));
t.ok(/circuit_fred_/.test(prometheus.metrics));
t.ok(/circuit_fred_.*perf/.test(prometheus.metrics));
t.ok(/circuit_bob_/.test(prometheus.metrics));
t.ok(/circuit_bob_.*perf/.test(prometheus.metrics));
t.ok(/circuit.*fred/.test(registry.metrics()));
t.ok(/circuit_perf.*fred/.test(registry.metrics()));
t.ok(/circuit.*bob/.test(registry.metrics()));
t.ok(/circuit_perf.*bob/.test(registry.metrics()));
t.ok(/circuit.*bob/.test(prometheus.metrics));
t.ok(/circuit_perf.*fred/.test(prometheus.metrics));
t.ok(/circuit.*bob/.test(prometheus.metrics));
t.ok(/circuit_perf.*bob/.test(prometheus.metrics));
prometheus.clear();
t.end();
});

test('The add function takes an object instead of just an Array', t => {
test('The add function takes an object instead of just an Array', async t => {
t.plan(3);
const c1 = new CircuitBreaker(passFail, { name: 'fred' });
const prometheus = new PrometheusMetrics();
prometheus.add(c1);
await c1.fire(1);
t.equal(c1.name, 'fred');
t.ok(/circuit_fred_/.test(prometheus.metrics));
t.ok(/circuit_fred_.*perf/.test(prometheus.metrics));
t.ok(/circuit.*fred.*/.test(prometheus.metrics));
t.ok(/circuit_perf.*fred.*/.test(prometheus.metrics));
prometheus.clear();
t.end();
});

test('The add function provides access to metrics for all circuits', t => {
t.plan(9);
const c1 = new CircuitBreaker(passFail, { name: 'fred' });
const c2 = new CircuitBreaker(passFail, { name: 'bob' });
const c3 = new CircuitBreaker(passFail, { name: 'foo' });
const prometheus = new PrometheusMetrics([c1]);
prometheus.add([c2, c3]);
t.equal(c1.name, 'fred');
t.equal(c2.name, 'bob');
t.equal(c3.name, 'foo');
t.ok(/circuit_fred_/.test(prometheus.metrics));
t.ok(/circuit_fred_.*perf/.test(prometheus.metrics));
t.ok(/circuit_bob_/.test(prometheus.metrics));
t.ok(/circuit_bob_.*perf/.test(prometheus.metrics));
t.ok(/circuit_foo_/.test(prometheus.metrics));
t.ok(/circuit_foo_.*perf/.test(prometheus.metrics));
prometheus.clear();
t.end();
});
test('The add function provides access to metrics for all circuits',
async t => {
t.plan(9);
const c1 = new CircuitBreaker(passFail, { name: 'fred' });
const c2 = new CircuitBreaker(passFail, { name: 'bob' });
const c3 = new CircuitBreaker(passFail, { name: 'foo' });
const prometheus = new PrometheusMetrics([c1]);
prometheus.add([c2, c3]);
await c1.fire(1);
await c2.fire(1);
await c3.fire(1);
t.equal(c1.name, 'fred');
t.equal(c2.name, 'bob');
t.equal(c3.name, 'foo');
t.ok(/circuit.*fred/.test(prometheus.metrics));
t.ok(/circuit_perf.*fred/.test(prometheus.metrics));
t.ok(/circuit.*bob/.test(prometheus.metrics));
t.ok(/circuit_perf.*bob/.test(prometheus.metrics));
t.ok(/circuit.*foo/.test(prometheus.metrics));
t.ok(/circuit_perf.*foo/.test(prometheus.metrics));
prometheus.clear();
t.end();
});

test('The add function called without parameter do nothing', t => {
t.plan(1);
const prometheus = new PrometheusMetrics();
prometheus.add();
t.notOk(/circuit_/.test(prometheus.metrics));
t.ok(/circuit/.test(prometheus.metrics));
prometheus.clear();
t.end();
});

test('Circuit fire/success/failure are counted', t => {
const circuit = new CircuitBreaker(passFail);
const fire = /circuit_passFail_fire 2/;
const success = /circuit_passFail_success 1/;
const failure = /circuit_passFail_failure 1/;
const fire = /circuit\{name="passFail",event="fire"\} 2/;
const success = /circuit\{name="passFail",event="success"\} 1/;
const failure = /circuit\{name="passFail",event="failure"\} 1/;
const prometheus = new PrometheusMetrics([circuit]);
t.plan(3);
circuit.fire(1)
Expand All @@ -142,11 +153,14 @@ test('Circuit fire/success/failure are counted', t => {

test('Metrics are enabled for all circuit events', t => {
const circuit = new CircuitBreaker(passFail);
circuit.on = (event, callback) => {
callback(null, 1);
};
const prometheus = new PrometheusMetrics([circuit]);
const metrics = prometheus.metrics;
t.plan(circuit.eventNames().length);
for (const name of circuit.eventNames()) {
const match = new RegExp(`circuit_passFail_${name}`);
const match = new RegExp(`circuit{name="passFail",event="${name}"}`);
t.ok(match.test(metrics), name);
}
prometheus.clear();
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